Gene May Increase Risk for Both Alzheimer’s and Heart Disease

Learning you carry a gene that increases your risk for Alzheimer’s disease can be distressing. But being told that the same gene also increases your risk for heart disease may lessen the distress and prompt you to make lifestyle changes that can benefit your overall health, researchers report.

“We found that telling individuals who wanted to learn about their risk for Alzheimer’s disease about their risk for both Alzheimer’s disease and coronary artery disease actually reduced distress among some people, and motivated many to make improvements to their lifestyles,” said Kurt Christensen, a researcher at Harvard Medical School and the lead author of the article. The findings appeared in the journal Annals of Internal Medicine.

The study looked at 257 men and women whose average age was 58. None had memory problems or other symptoms of Alzheimer’s disease. They filled out questionnaires about their exercise habits, and also got psychological tests for signs of anxiety and distress. They also agreed to undergo genetic testing to see whether they carried the E4 version of the APOE gene, which is associated with an increased risk of developing Alzheimer’s disease in old age.

Those in the study were then randomly assigned to one of two groups. In one group, which served as a control, genetic counselors told them about their risk for Alzheimer’s disease, based on whether they carried the APOE-E4 gene.

The other group got the same information about their Alzheimer’s risk, based on APOE testing results. But those who carried the APOE-E4 gene were also informed that studies have found that that form of the gene also raised their risk of developing heart disease. They were also counseled that stopping smoking, maintaining a healthy diet and weight, treating high cholesterol, and exercising could lower their risk of developing heart disease.

The study participants again underwent psychological assessments and filled out questionnaires about their lifestyle habits six weeks after the genetic counseling session, and again at six months and a year after their the results of their genetic tests.

The researchers found that those who were told they were at increased risk of Alzheimer’s but who also were told about their increased risk for heart disease had less anxiety and distress than the control subjects, who were told only about their Alzheimer’s risk. In addition, those who got information about heart disease risks were also more likely to be making improvements to their diet and exercise routines.

“This research is reassuring, and provides evidence that secondary genomic findings disclosure can have a substantial positive psychological and behavioral impact on patients,”said Dr. Robert C. Green, a medical geneticist at Brigham and Women’s hospital and the study leader. Participants who were told about their heart disease risk may have felt empowered to make changes about a disease that they could prevent, the researchers say.

Dr. Green cautions, however, that providing genetic testing results carries risks, and that such information may harm patients more than it helps, including an increased risk of depression, anxiety and other mental health problems. That’s one reason why many experts advise against widespread genetic testing for Alzheimer’s at this time, particularly for those who remain mentally intact and show no signs of the disease.

What’s more, testing can be expensive, and health insurance may not cover the cost. Even more important, there is still no effective means of preventing or curing Alzheimer’s. Drugs are available, but they have only limited effectiveness in some people and do not stop the eventual downhill progression of disease.

Ultimately, the choice of whether to get a genetic test remains a personal one. All the more reason it’s important to be informed about the pros and cons of Alzheimer’s screening and what doctors know about genes and your risk for the disease.

Whether you carry the APOE-E4 gene or not, many other risk factors likely contribute to Alzheimer’s, not just genes and old age. What you eat, how much you exercise, formal education, smoking, how mentally active you remain, and other factors have all been implicated as possible factors that may contribute to Alzheimer’s progression. In fact, in one study of elderly men and women living in Utah, more than a fourth of those who carried the APOE-E4 remained Alzheimer’s-free, even up to age 100.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.